"I can't move it!" Mr. Sharp yelled. "It's jammed! I can't shut off the gas! Run! Look out! She'll explode!"
Tom Swift, the young inventor, whose acquaintance some of you have previously made, gave one look at the gauge, and seeing that the pressure was steadily mounting, endeavored to reach, and open, a stop-cock, that he might relieve the strain. One trial showed him that the valve there had jammed too, and catching up a roll of blue prints the lad made a dash for the door of the shop. He was not a second behind his companion, and hardly had they passed out of the structure before there was a loud explosion which shook the building, and shattered all the windows in it.
Pieces of wood, bits of metal, and a cloud of sawdust and shavings flew out of the door after the man and the youth, and this was followed by a cloud of yellowish smoke.
"Are you hurt, Tom?" cried Mr. Sharp, as he swung around to look back at the place where the hazardous experiment had been conducted.
"Not a bit! How about you?"
"I'm all right. But it was touch and go! Good thing you had the gauge on, or we'd never have known when to run. Well, we've made another
